X-ray apparatus



Dec. 7, 1948. x. RINGLER 2,455,522

XRAY APPARATUS Filed April 8, 1,944 2 Sheets-Sheet l AUTD TRANS FORMER BUTTONS v fig 5.

AMPERE SE IN VEN TOR. /V//VG INGLEK.

ATTORNEY KILOVDLTAQE PEAK De@ 7# 1948- LRINGLER 2,455,522

x-RAY APPAIEATUS AT'OKNEY Patented Dec. 7, 1948 UNITED STATES FFICE 2,455,5:iaf` l y l 's 's A Irving ltinglenew York, N. Y. Application April' s, 1944, s'al N6; 530,163

Claims.

This invention relates to X-ray apparatus. The technician, who operatesV X-ray equipment to produce certain results therewith, must calcue late or otherwise determine the proper maximum voltage to be impressed upon the X-ray bulb; some technicians use "rule of thumb 'methods methods which are essentially founded uponr pure guesswork. Even where the technician has attempted to reach a determination by calculation, the factors upon which he has had to relyin the past, have been mostly in the same category; that is, rule of thumb. However, it has been determined, lby experimentation, that a number of factors must be considered for the purpose of determining the proper voltage to be applied. As

those factors vary, so will the voltagev vary.v It has been observed that the factors vary in certain relations to each other, as Well as in relation to the voltage. I

For instance, the voltage to be applied varies in relation to the part of the body which is to be X-rayed. The density of the part, and' its position within the body, are determining factors. Thus, whether it is desired to X-ray the'lungs, or to X-ray the ribs, the voltage required for proper exposure of the X-ray film willjbe different. Then, again, the current applied to the filament of the bulb, and the time of exposure, that is, the number of milli-ampere seconds, will determine the variation in voltage required. The current applied, and the time of application, will be varied by the technician as he observes the patient. When he observes that the patient is of the nervous type, the technician may determine to decrease the time of exposure. He may determine to increase the current, or to eifect his compensation by adjusting the voltage.

Increase of the distance of the object to be X-rayed from the X-ray bulb will require inlcrease of the applied voltage. It has been discovered that whether the person to be X-rayed is an adult or infant must be taken into account,v and, in that connection if the subject is under the age of 12, whether the X-ray is to -bel of thoracic tissue or of a non-thoracicpart. If the party is adult, that is, over the age of 12, it has been discovered that it seems to matter little Whether the part to be X-rayed is' thoracic or non-thoracic; a constant is involved.

A further factor controlling the requisite volt' age resides in the thickness of the part itself.

Finally, exposure to X-rays may be performed under a plurality of techniques. In one technique, a screen, known as the Potter-Bucky diaphragm, may beused. In such case,

' 2 technique' is comonly. known bythe term, bucky. Another technique utilizes', anormal screen, and may li-designated asthe non-bucky technique. TheBuckyT requires" a vhigher voltagebecause of greaterabsorptionyof energy. It `has been found, new ver, tnattneyoitage' to bge applied when the bucky" isusedjdoesinot differ from the voltage v'vitlijthe",non-bucky technique bya constant dier'ert'ial,. Thevariation involtage for the buicky, all other 'factors beine; rconstant and considered, have been determined by experimenta- IL It'iisansjobject- ,of` the invention to provide va device' withvfhich a technician may determine with facility', .from such assumptions" as he may mak rand from such known factors" orv known rela ion "ofvthe'selfactorsl, and those facts which the, tfchiicianlrnay, determine from' observation of av subject patient, the reqm'red unknown factor or fac'ztcrs`-'4 fo akiri'ga proper X-ray' exposure. `It` is' an object of the' invention tioprovide a device which functions asV a slide rule, by which the 'determination' of `peak voltage for proper exposure byxfrjayequiprnent will be facilitated from certair'i known or determined factors which vary oil :21.L'i's`e`v variation of such peak voltage according to observations' previously' made'.

)It is'an object ofthe invention to providev apparatus" in conjunction, with Xray equipment, by" vvlfnc'zh' the varyingfactors entering into the prducticn of `angr-*ray may be related' to each other" 'determining' the unknown factors of X-rayy ,equipment` operation.

It' isan'obj ect of the inventionto provide X-ray equipment havin'gla'n adjustable' control' for peak voltage'v applied to the X'ray bulb, by which the tech` ci'ariayautomatically set the apparatus foiilthe' required voltage, by setting the device in accordance' with certainl known or selected factors. Y p

It is' anV object of the invention to resolve the raclio'graphi'c4 technique into factors such that theym'aly belassociatedfwith and be applied in the Aoplefr 'tionpf aslide rule. Y

It is,an.ho,bj.ectvof vthe invention to eliminate, tolasvA greatT a,A degree as1 possible,` the matter of arbitrarinessnn. determining factors for X-ray work, and als'ontdeliminate' the usual trial' and error" methods followedlin determining these' fac? tors. In-thi's'relation, itis welll recognized that the* dterminations of thef proper voltages for X-'ray' exposures is a matter related not only to saving time and @est from obtaining immediate and accurate exposures, but also to the safety of 3 the patient, in guarding against over-exposure, or damage from unnecessary repeated exposures.

Much of present day X-ray practice is rule-ofthumb, and fails to give consideration to factors such as the physical properties of X-rays of varying wavelengths. Yet variation of the voltage impressed upon the X-ray tube causes change in the wave length of the X-ray emitted.

It is an object of the invention to provide apparatus for use in operating X-ray apparatus which will function to eliminate, to as great a degree as possible, the rule-of-thumb in determining the factors in such use, and to compensate, as much as possible, for the effects of variations of wave length of the X-rays as the voltage impressed upon the tube varies.

As the result of investigation and observation, it has been determined that the factor for converting from the voltage necessary for exposure with the non-bucky technique to -that with a Potter-Bucky diaphragm is not a constant, as has been .the usually accepted theory. It has been determined that the conversion factor Varies directly with the kilovolts impressed on the plate of th-e X-ray tube.

It is an object of the invention to provide a method of determining ythe peak voltage to be applied rto an X-r-ay tube by which compensation is made automatically for differential differences between required voltages for non-bucky technique or bucky operation.

The determinations herein are discussed with relation to the voltage, or peak voltage, applied to the X-ray tube, in order to obtain the desired radiation for a proper exposure. Thus, two of the scales discussed -are considered in terms of voltage.

However, it is apparent that the scales could be graduated in terms of wave length, absorption coefficients, the R unit, or some similar physical measurement in place Iof the kilovolts peak, or k. v. p., considered herein, without varying from the principle of the invention.

It is an object of the invention to provide means by which substantially all factors, or combinations of factors, governing proper X-ray exposure, will be considered in computation, and wherein all `such factors enter quickly and accurately into such computations.

Other objects of this invention will be set forth hereinafter, or will be apparent from the description and the drawings, in which are illustrated embodiments of apparatus for carrying out the invention.

The invention, however, is not intended to be restricted to any particular construction, or to any particular arrangement of parts, or to any particular :application of any such construction or any such arrangement of parts, or to any specific method of operation, or to any lof the various details thereof, even where specifically shown and described herein, las the same may be modified in various particulars, or may be applied in many varied relations, without departing from the spirit .and scope of :the claimed invention, practical constructions embodying certain details of the invention being illustrated and described, but only for the purpose of complying with the requirements of the statutes for disclosure -of operative embodiments, land without attempting to disclose -all of the various forms and modifications in which the invention might be embodied.

On the drawings, in which the same reference characters refer to the same parts throughout, and in which are disclosed such practical constructions:

Fig. 1 is a plain View of a slide rule embodying features of the invention;

Fig. 2 is a transverse cross-sectional view, on the line 2 2 of Fig. 1;

Fig. 3 is a diagram showing' the method of calibrating X-ray apparatus against slide rule `readn ings;

Fig. 4 is a diagram illustrating the rate of increase of voltage w-hen .the bucky is used as against non-buclry technique;

Fig. '5 is a diagram showing the relation between nulli-ampere seconds and kilovoltage peak;

Fig. 6 is a diagrammatic view, illustrating the manner in which a slide rule of this type may be incorporated into iii-ray apparatus, :automatically -to control the voltage delivered to the /--ray tube in accordance with slide rule determinations;

Fig. 7 is lan enlargement of a portion of Fig. 6, illustrating the relation of the slide rule to the auto-transformer and automatic operation of the X-ray tube upon setting the slide rule; and

Fig. 8 is a transverse cross-sectional view, substantially centrally of the hairline carrier in Fig. 7, and through the slide rule and the panel asso- -ciated therewith.

Slide rule li) may consist of a base i2 of wood, plastic or similar material. The base may be built up or otherwise formed to provide a groove or depressed section M between a pair of raised p1atforms i6 and lil. A slide 2d may be mounted in and retained for sliding movement relative to platforms it and it. The side walls 22 of slide 2li and the walls 2li of platforms ii and i3 facing into groove I4 may be formed or otherwise constructed to provide interlocking grooves 25 and fins 28. The fins are received in the grooves so that slide lill will be retained firmly in gro-ove i4, as slide 2li is permitted sliding movement relatively to base l2.

Slide 20 is in turn formed substantially of material the 'same as base l2. In this case, slid@ 2l takes the form of a body portion 3B having a plaitforin 32 formed or otherwise provided thereon and extending upwardly therefrom at one edge eX- tremity thereof. At the other edge extremity, slide 28 is provided with a thin wall form-ation 34. lFins 28 are formed on the outer faces of platform 32 and wall 34.

Between platform 32 and wall 34 is a groove 35, in which a slide t8 may be retained for sliding movement relative to slide 2U. Walls 45S of groove 36 and the side walls di? of slide 38 may be formed with interlocking grooves lid and fins llt to retain slide 38 with relation to slide 2d, and yet permit adjustment of slides and 33 with relation to each other and to base l2. l

A hairline carrier LEE, of the usual type, may be provided to straddle base l2. Carrier d3, in the usual manner, may comprise a frame 5d having apair of bent arms 52, the ends tid of which are bent towards each other. The arms are to be engaged in grooves 55 provided in side walls 5t o f base l2. Frame bil may retain a glass piece Gil or the like in which a hairline may be formed. This hairline will co-operate with scales 54, 56, 68, 10, l2, 'M and 7S in the usual manner of slide rule hairlines, and in accordance with the further descripticn.

Scale 54 may be provided upon a face 'i8 which is the top-most portion of platform it. Scale 64 is graduated in terms of the factor of density of the part to be X-rayed. Any arbitrary dimension may be assumed for graduation of the scale in accordance with this factor, or the dimension may be determined in accordance with a dimension assumed for any one of the other scales. In

theinstance illustrated, the dimension of graduations Sil, shown demarcated on face 18, was arrived at by pasting on face 18 a piece of graph paper having ten divisions per inch. A zero point was adoptedr at line 82, and was marked with the symbol, SEL--1 each box on either side of this Zero line was taken to indicate ten units, and was so indicated by notations 84 to indicate the relation of the particular graduations to different parts of the body. Scale Eil thus is one scale, but in terms of two markings, that is, the Part of the body, and the Density of that part to be X-rayed.

Scale 4 includes substantially all anatomical parts. The particular graduations depicted comprise eighty units or intervals, from +40 to 40. It has been determined in practice that the varying densities of the parts of the human body can be reduced, for radiographic purposes, to a simple set of coordinates. or purposes of illustration, the intervals on scale @4 have been denoted as follows:

a. LU AP +38: Lung anterior posterior projection.

b. LU LAT +24: Lung lateral projection.

c. D SP LAT +20: Dorsal spine lateral projection.

d. (RIB ST) (LSP LAT) +10: Ribs and sternum; lumbar spine lateral projection.

e. (VISC) (D SP) (AP) +5: Visceral organs, gastro-intestinal tract; gemito-urinary tract; gall bladder; bladder; liver; spleen.

f. SK N: Skeletal; includes all extremities;

pelors; hips; antero-po-sterior projection of lumbar spine.

g. No-SC-l6: Ncnscreen film; a special rapid fine grain film that is exposed in cardboard exposure holders and eliminates fluorescent screens.

h. HO34: This is the technique that is used with standard films in cardboard exposure holders.

On face 8S of platform 32 are the two scales 66 and the inilli-ampere seconds scale and the target distance scale, respectively. The graduation of these scales must now conform to the dimensions adopted either for scale or whatever scale has had an arbitrary dimension adopted for it. For the purposes of clarity in continuing this description, it is assumed that the dimension for graduations 8@ was the arbitrary assumption. Thus, scale 55, for the millianipere seconds, must conform to this dimensioning. also must conform to the relationship which has been found to exist between the current-time factor and the peak voltage factor. Of course, a degree of arbitrariness can still be exercised in determining the proper dimensioning for graduations 88 of scale "66 since, in the final result, the variation can be taken up in graduation of scales 74 and '16. The same method may be followed in determining the dimensions of graduations 9i] of scale 68.

It will be noted that scales 'd and 68 must be related to each other, since adjustment of scale E6, the milli-arnpere seconds scale, with relation to scale Sil, the density scale, immediately sets scale 68, the target distance scale, relatively to the voltage scales lll and ll.

It will be noted that the indicia for graduations 88 are not in a regular progression as are graduations 89. This results from taking into account the relation between peak voltage and milli-ampere seconds, shown by the curve illustrated in Fig. 5. This curve was determined from a special E. I. Photometriograph in which kilovolts inipressed on plate were plotted against millieampere seconds. For such a plot, substantially all other factors were maintained constant, While either voltage or current w-as varied. The relationship determined has been found to be constant for substantially all thicknesses of part.

The subject of scalevGB, target distance, has been the subject of experimental determination, since Roentgens inverse square law, while correct on basic concepts of physics, has its shortcornings in radiographic practice. For instance, the sensitivity curve of X-ray film limits the operation of this law. Furthermore, serious variations have been found to exist in the hard and soft ends of the Xr'ay spectrum, as they are applied in medica1 work. For instance, one set of determinations shows that the lower the voltage, the smaller the conversion factor as based upon an increase of distance. Likewise, it has been ascertained that either the harder' rays or higher voltage will require higher voltage per unit of distance as the distance from target lm to X-ray tube increases.

On face 92 of slide 38 are scales 1D and 12 which are concerned, respectively, with whether theY patient is an adult or an infant, and, in the latter case, whether the part to be X-rayed is thoracic or non-thoracic, and With the thickness of thev part to be X-rayed. Scale lll is made necessary by a condition observed in practice. In the case of persons of i2 years or younger, a compensating factor must be introduced. This factor is found to vary not only in relation to thev age of the patient, but also, in different fashion, by reason of whether the X-ray is to be made of matter which is thoracic or non-thoracic- It has been found that the peak Voltage for proper X-ray exposure increases with increase of age when thoracic tissue is to be X-rayed. On the other hand, it has been found that the peak voltage for proper X-ray exposure decreases with in: crease of age when the part to be X-rayed is. nonthoracic.

Scale 'l is graduated in such manner as to compensate for these variations in the types of matter, where the subject is of such age that the density of the matter has not as yet become uniform. If the slide rule were to be used only on subjects older than l2 years, scale 'ill could be dispensed with. In such case, the single indication 94, marked Adultf to which scale le is set 'when the patient is over l2 years old, would be all that would. be necessary.

Scale 'I2 is graduated in terms of the actual thickness (in this instance, in centimeters) of the part to be X-rayed. It has been foundv that, contrary to conventional practice, kilovoltage peak is not a constant function of the thickness of a part without regard to changing photographic effects per centimeter change. For instance, in the lower kilovolt'ages, the change per centimeter has been found to be about two kilovolts, while in the higher voltages, the change per centimeter has been found to be three kilovolts. Thus, scale 12. is graduated in accordance with this variation in relationship, to compensate in the nally determined peak. voltage,

On face 96 of platform I8 are scales 'M and' 16. It will be noted that while substantially the same spacing of indications e8 is shown, there isv variation in valuel of such spacing on the two scales, that is, the two scalesY do not vary at the same rate'. The rate of variation in these two scales,` which arev thev peak voltagesforusewith the against the increase necessary ywhere the bucky is utilized.

Aside from all of these determinations, which have been reached by experiment, it also has been determined that the readings of the meters of X-ray apparatus are so inaccurate that, when the slide rule is rst used with any piece of X-ray apparatus, it is necessary to associate the slide rule with such X-ray apparatus by calibration. The slide rule itself is standardized against an X-ray machine which has been accurately calibrated. The modern high tension measurements have been found to be too inaccurate for the exact work required by such calibration. The different types of apparatus for the purpose of determining the voltage relations `between two pieces of apparatus have been found to vary widely in performance and accuracy under varying climatic conditions, or to vary in eiciency. The end product of X-ray apparatus is the effect upon the X-ray nlm. For that reason, photometric calibration of the apparatus has been found most desirable.

For instance, a reading of voltages with an X-ray screen may be taken for exposures for certain parts of the body to obtain proper exposures. A number of these readings are plotted as a graph against the readings for voltage upon the slide rule for the same values of parts, milliampere seconds, and target distance. A graph for such purpose is shown in Fig. 3, Where the calibration was effected for apparatus |00, to be described, where the slide rule had been incorporated into the control panel of X-ray apparatus.

In order that a more accurate factor may be used in place of maximum voltage, or kilovolts peak, or k. p. V., as it is usually abbreviated, a factor such as wave length, or the R units may be substituted for the indications. This, of course, would require some eicient indicating device for any of these units of graduation.

In the operation of the slide rule in conjunction with X-ray apparatus, the technician manipulates hairline 62, after he has set the different scales in accordance with determined factors or assumed factors, to read, on scales 14 and 16, the peak voltage required when the nonbucky technique or the .bucky is used. For instance, if the technician knows that he is to X-ray the bone structure of the ribs, and not the tissue structure of the lungs, he will set hairline 62 at the position marked, Ribs, on scale 64. Then he will move slide 20, in accordance With his predetermined purpose of a fast or slow eX- posure. This, of course, he would determine by observing the patient. If he observes that the patient would not remain quiet under long exposure, the technician knows that the number of milli-ampere seconds alloted must be low. The technician, therefore, determines for himself the time of exposure, and sets scale 66 with relation to scale 64 accordingly, of course using hairline 62 for accuracy. Now, scales 64 and 66 are related, and the technician now must determine what distance from the subject he will position the X-ray bulb. This, of course, will depend upon a number of factors known to the technician, and

observed by him in relation to the patient. This target distance is the distance of the X-ray tube from the lm. Usually it may be read upon the scale on the apparatus, as the bulb is moved towards or away from the patient. When this distance is determined, carrier 48 is moved to bring line 62 into registry `with that reading on scale 68.

The technician will have observed, of course whether the patient is an adult or of or under 'the age of l2. In the event the patient is adult, indication 94 on scale I0 will be brought into registry with the hairline, and no further adjustments will be required in that connection. However, if the patient is under the age of 12, and, of course, the age will be known, slide 38 will be moved to bring the proper graduation on scale I0 into registry with the hairline. This, of course, would be determined by whether thoracic or nonthoracic matter were to be X-rayed.

Before the exposure will have been made, the particular part to be X-rayed would have been measured. After slide 38 has been adjusted as previously described, carrier 48 is now adjusted` to bring hairline 62 into registry with the proper graduation for thickness of part on scale '|2. The technician now may read, either on scale T4 or scale Til, the proper peak voltage to which the apparatus will be set to make a proper X-ray exposure.

As shown in Fig. 6, this principle may be appropriated to X-ray apparatus |00 itself, which may include the usual elements of such X-ray apparatus. In this case, the slide rule is made a part of panel 52 upon which may be mounted certain of the parts of the apparatus. Mounted on or beneath that panel may be an auto-transformer 04 by which the voltage applied to the X-ray tube is controlled. The mains |05 from the electric power source are connected to this autotransformer. One of the mains is also connected to a switch ID'I, that main also having the overload breaker H5 connected therein. This switch is connected to a step-up transformer IBB. The step-up transformer is connected to suitable rectifying means I I. From the rectifying means is derived the voltage for application to X-ray tube A plurality of taps It are taken off transformer EIM, and are led to two sets of contacts |08 and lill, Such contacts are in separate lines spaced apart from each other. Each tap |06 may be led to a contact |08 or a contact lill. In some cases, the same tap may be connected both to a Contact illil and to a contact I I0. In such cases, the associated contacts I ii and H0 will not be at the same position transversely of panel |02 since they are to effect variation in peak voltage for nonbucky or bucky, just as scales 14 and 'I6 compensate for these differences.

A base I l2, similar to base I2, may have a scale ||4 similar to scale 54 graduated on a face H6. A slide I I8 may be mounted with relation to base I I2 in a manner similar to slide 20. Slide I I8 may carry scales IZI! and |22 disposed thereon in a manner similar to scales 66 and 63. Slide ||8 may also carry slide |24, which may be graduated with scales |26 and |28 similar to scales 'l and 12.

A carrier I3@ having a hairline |32 may likewise be mounted upon base |l2, for movement with relation to that base in adjusting line |32 with relation to the different graduations. Carrier |30 may comprise a body |34 having arms |36 engaged in grooves |38 in the vside faces |40 of base- H2. Body |34 may have an opening M4 Vvat which -a glass |45 may be retained. Upon glass ljli., hairline |32 may be etched. i r

Body 34 may carry a contacter |55. iis contactor may be carried 4at the end of an arm: |51 projecting laterally from body |34 andv may include a roller contact 45theld in engagemenhby means of a spring, with contact rail |68. Con7 tact rail |50 is electrically connected'to oneside cf switch lill. Furthermore, a second contacter |62 is provided to ride upon and along contacts |98 or contacts l ii. Contacter |62 may comprise an arm |53 extending laterally from body |34 in a direction opposite the projection of :arm |57. Carried and slidable upon arm |53 is a `sleeve |55'. A pin l? extending from arm |63 into a slot lll in sleeve |55 provides limits for movement of sleeve |35 with relation to arm |53. Electrical connection is eifected between sleeve 'l F35 and armv |63. An additional arm |59, substantially parallel to |53, bears indicia lll. A pointer HB, carried by sleeve |55. indicates the adjusted position, with relation to contacts |08 and Hl, `of a spring-pressed shoe i755 at the end of sleeve |55, that is. whether the adiustment is for bucky or non-bucky technicue. To'perrnit manipulation of the sleeve without danger to the technician, a knob |75 of non-conducting materials isafixed to sleeve |65. Electrical connection betweencontactors |55 and |62 is made by a conductor 'lill which may be molded or otherwise embedded or retained within body |34, or insulated to protect the technician. Thus, the technician, on adjust-4 ing the slides l i8 and |24 with relation to thebase, and sleeve L55 with relation to armV |63, autornaticallgT would determine the voltage to be applied to the bulb. Y l l Many other changes could beefectedein the particular apparatus designed, andin the method of operation set forth, and 'in specific details` thereof, without substantially departing from the invention defined in the claims. the specific-.description being merely of operative embodiments capable of illustrating certain principles of the invention. v

What is claimed as new and useful is:

l.. A calculating device for use in controlling the operation ci X-ray apparatus, comprising a pair or spaced apart, naedly related scalecarrying members, one of the members carrying a scale graduated in terms of the densities of the parts to be X-rayed, the other member'carrying a scale graduated termsof X-ray radiation necessary, and a plurality of membersvrnovable between the tivo relatively lined. .nier/libere',` one movable member being contiguous to the fixed fr Jubel carrying the scale of density of the part, said one movable member carrying a'scaie cali-A brated in terms of product of the'tirne Aof sure and the current necessary for' heating nent `of the X-ray tube and another scale calibrated in terms of the distance ofv the part to be Xqayed to the X-ray tube of the Xeray apand the other movable member carrying a scale graduated terrns of the thickness of the part to be X-rayed, said one movable member being adjusted to associate a selected graduation of said product of time and current necessary for lament heating with the graduation for density of the part to be X-rayedfsaid other movable member beinfr adjusted between the said' one movable memberand the scale oirl'Xeray ra-. diation to associate a scale graduation on the'.

othermovable member with the scale on said one movable member for a distance between part and X-ray tube to determine from the resultant association of the graduation for the thickness of the part to be X-rayed with a graduation on the scale of.X-ray radiation the X-ray radiation necessary to effect an X-ray for the part involved. 2. A calculating device for use in controlling the operation of X-ray apparatus, comprising a pair ci. spaced apart, xedly related scale-carrying members, one of themembers carrying a sc ale graduated in terms of the densities of the parts to beYX-rayed, the other member carrying a scale graduated in terms of X-ray radiation necessary,k and a plurality of members movable between the two relatively xed members, one movable member being contiguous to the xed member carrying the scale yof density of the part, said one movable member carrying one scale calibrated in terms of the product of the time of exposure and the current necessary for heating thelament of the X-ray tube and another scale calibrated in terms of the distance of the part to be` X-rayed to the X-ray tube of the X-ray apparatus, and the other movable member carrying a scale graduated in terms of the thickness of the part to be X-rayed, and a scale calibrated in` terms of the age of the individual to be X- rayed on the basis of whether the part to be X-rayed is thoracic or non-thoracic, said one movable member being adjusted to associate a selected graduation of said product of time and current necessary for lament heating with the graduation for density of the part to be X-rayed, said other movable member being adjusted to associate the graduation for the age of the individual to be X-rayed with the scale on said one movable member for the distance between the part and X-ra-y tube to determine from the resultant association of the graduation for the thickness of the part to be X-rayed with a graduation onv the scale of X-ray radiation the X-ray radiation necessary to eiect an X-ray for the part involved. f

3; A calculating device for use in controlling the operation. of X-ray apparatus, comprising a pairof spaced apart, xedly related scale-carrying members, one of the members carrying a scale graduated in lterms of the densities of the parts to be X-rayed, the other member carrying apair of scales one graduated in terms of X-ray radiationnecessary when a normal screen is used and the'other in terms of variations in the X-ray radiation necessary when a Bucky screen is used, and a plurality of members movable between the two relatively fixed` members, one movable member beingfcontiguous to the Xed member carrying the scale of density of the part, said one movablewrnember carrying one scale calibrated in terms of the vproduct of the time of exposure and the current necessary for heating they filament of? the X-ray tube and another scale calibrated in terms ofthe distance from the part to be X- rayed to the X-ray tube of the X-ray apparatus. and the other movable member carrying a scale graduated in terms yof the thickness of the part to` be X-rayed` and another scale calibrated in terms of the age of the individual to be X-rayed on the basis of whether the 'part to be X-rayed is thoracic or non-thoracic, said one movable member being adjusted to associate a selected graduation of said product of time of exposure and the current necessary for lament heating with thegraduation fori densityv of `the part to be X-rayed'saidf other movable member being adjusted to associate the graduation for the age of the individual to be X-rayed With the scale on said one movable member for the distance between part and X-ray tube to determine from the resultant association of the graduation for the thickness of the part to be X-rayed with a graduation on the scales of X-ray radiation the X-ray radiation necessary to effect an X-ray for the part involved.

4. X-ray apparatus including an X-ray tube, and means for supplying anelectrical potential to the X-ray tube, the supplying means including a circuit member, and means for controlling the member for imposing on the X-ray tube the proper potential for the production of the required X-ray radiation; said controlling means including a scale-carrying member substantially xedly related to the circuit member, the scalecarrying member including a scale graduated in terms of the densities of the parts to be X-rayed. the circuit member having means for producing calibratedly varied potentials at its various positions in relation to the scale of the scale-carrying member, and a plurality of members movable between the scale-carrying and circuit members, one movable member being contiguous to the circuit member, said one movable member having a scale calibrated to superimpose on the iixed relationship between the scale-carrying and circuit members for each graduation on the xed scale-carrying member a factor in terms of the thickness of the part to be X-rayed, the movable members also providing means for superimposing upon said fixed relationship a factor in terms of the distance between the object to be X-rayed and the X-ray tube, to determine from the resultant association of factors on the movable members with said fixed relationship the potential necessary to produce the radiation required for the X-ray of the part involved.

5. X-ray apparatus including an X-ray tube, and means for supplying an electrical potential to the X-ray tube, the supplying means including a circuit member, and means for controlling the member for imposing on the X-ray tube the proper potential for the production of the required X-ray radiation; said controlling means including a scale-carrying member substantiallyv xedly related to the circuit member, the scale- `carrying member including a scale graduated in terms of the densities of the parts to be X-rayed, the circuit member having means for producing calibratedly varied potentials at its various positions in relation to the scale of the scale-carrying member, and a plurality of members movable between the scale-carrying and circuit members, one movable member being contiguous to the scale-carrying member, said one movable member having a scale thereon calibrated to impose on the fixed relationship between the scale-carrying and circuit members for each graduation on the iixed scale-carrying member a factor in terms of the product of the time of exposure and the current necessary for heating the lament of the X-ray tube, the other movable member having a scale graduated in terms of the thickness of the part to be X-rayed and being located in juxtaposition to and being adjustable to locate its scale with relation to the circuit member, the movable members also providing means for superimposing upon said xed relationship a factor in terms of the distance between the object to be X-rayed and the X-ray tube, to determine from the resultant association of factors on the movable members with Said iiXed 12 relationship the potential necessary to produce the radiation required for the X-ray of the part involved.

6. X-ray apparatus including an X-ray tube, and means for supplying an electrical potential to the X-ray tube, the supplying means including a circuit member, and means for controlling the member for imposing on the X-ray tube the proper potential for the production of the required X-ray radiation; said controlling means including a scale-carrying member substantially xedly related to the circuit member, the scalecarrying member including a scale graduated in terms of the densities of the parts to be X-rayed, the circuit member having means for producing calibratedly varied potentials at its various positions in relation to the scale of the scale-carrying member, and a plurality oi members movable between the scale-carrying and circuit members, one movable member being contiguous to the scale-carrying member, said one movable member carrying scales one of which is calibrated in terms of the product of the time of exposure and the current necessary for heating the lament of the X-ray tube, the other movable member having scales one of which is graduated in terms of the thickness of the part to be X-rayed, said other .fmovable member being located in juxtaposition to and being adjustable to locate its said scale with relation to the circuit member, to determine from the resultant association of factors on the movable members with said xed relationship the potential necessary to produce the radiation required for the X-ray of the part involved.

'7. X-ray apparatus including an X-ray tube, and means for supplying an electrical potential to the X-ray tube, the supplying means including a circuit member, and means for controlling the member for imposing on the X-ray 'tube the proper potential for the production of the required X-ray radiation; said controlling means including a scale-carrying member substantially xedly related to the circuit member, the scalecarrying member including a scale graduated in terms of the densities of the parts to be X-rayed, the circuit member having means for producing calibratedly varied potentials at its various positions in relation to the scale of the scale-carrying member, and a plurality of members movable between the scale-carrying and circuit members, one movable member being contiguous to the scale-carrying member, said one movable member carrying scales one of which is calibrated in terms ofA the product of the time of exposure and the current necessary for heating the lament of the X-ray tube, the other movable member having scales one of which is graduated in terms of the thickness of the part to be X-rayed, and the other of which is calibrated in terms of the age of the individual to be X-rayed on the basis of whether the part to be X-rayed is thoracic or non-thoracic, said other movable member being located in juxtaposition to and being adjustable to locate its said scales with relation to said one movable member and said circuit member to determine from the resultant association of said other movable member with the circuit member the potential necessary to produce the radiation required for the X-ray of the part involved.

8. X-ray apparatus including an X-ray tube, and means for supplying an electrical potential to the X-ray tube, the supplying means including a circuit member, and means for controlling the member for imposing on the X-ray tube the proper potential for the production of the required X-ray radiation; said controlling means including a scale-carrying member substantially fixedly related to the circuit member, the scalecarrying member including a scale graduated in terms of the densities of the parts to be X-rayed, the circuit member having means disposed in relation to the scale of the scale-carrying member for producing calibratedly varied potentials at its various positions in relation to whether a normal screen is used or a Bucky screen is used, and a plurality of members movable between the scale-carrying and circuit members, one movable member being contiguous to the scale-carrying member, said one movable member carrying scales one of which is calibrated in terms of the product of the time of exposure and the current necessary for heating the filament of the X-ray tube, the other movable member having scales one of which is graduated in terms of the thickness of the part to be X-rayed, and the other of which is calibrated in terms of the age of the individual to be X-rayed on the basis of Whether the part to be X-rayed is thoracic or non-thoracic, said other movable member being located in juxtaposition to and being adjustable to locate its said scales with relation to said one movable member and said circuit member to determine from the resultant association of said other movable member with the circuit member the potential necessary to produce the radiation required for the X-ray of the part involved.

9. X-ray apparatus including an X-ray tube, and means for supplying an electrical potential to the X-ray tube, the supplying means includ- 12 ing a circuit member, and means for controlling the member for imposing on the X-ray tube the proper potential for the production of the required X-ray radiation; said controlling means including a scale-carrying member substantially l,

xedly related to the circuit member, the scalecarrying member including a scale graduated in terms of the densities of the parts to be X-rayed, the circuit member having means disposed in relation to the scale of the scale-carrying member for producing calibratedly varied potentials at its various positions in relation to whether a normal screen is used or a Bucky screen is used, a plurality of members movable between the scalecarrying and circuit members, one movable member being contiguous to the scale-carrying member, said one movable member carrying scales one of which is calibrated in terms of the product of the time of exposure and the current necessary for heating the lament of the X-ray tube, the other movable member having scales one of which is graduated in terms of the thickness of the part to be X-rayed, and the other of which is calibrated in terms of the age of the individual to be X-rayed on the basis of whether the part to be X-rayed is thoracic or non-thoracic, said other movable member being located in juxtaposition to and being adjustable to locate its said scales with relation to said one movable member and said circuit member, and a member movable with relation to the flxedly related scale-carrying and circuit members and the movable scale-carrying members for determining the eiective potential for the circuit member in accordance with the position to which said other movable member is adjusted with relation to said one movable member.

10. X-ray apparatus including an X-ray tube, and means for supplying an electrical potential to the X-ray tube, the supplying means including a circuit member, and means for controlling the member for imposing on the X-ray tube the proper potential for the production of the required X-ray radiation; said controlling means including a scale-carrying member substantially xedly related to the circuit member, the scalecarrying member including a scale graduated in terms of the densities of the parts to be X-rayed, the circuit member having means disposed in relation to the scale of the scale-carrying member for producing calibratedly varied potentials at its various positions, a plurality of members movable between the scale-carrying and circuit members, one movable member being contiguous to the scale-carrying member, said one movable member carrying scales one of which is calibrated in terms of the product of the time of exposure and the current necessary for heating the filament of the X-ray tube and the other of which is graduated in terms of the distance from the object to be X-rayed to the X-ray tube, said one movable member being movable to position a graduation of one of its scales in relation to one of the graduations of the scale of density of part, the other movable member having thereon scales one of which is graduated in terms of the thickness of the part to be X-rayed, said other movable member being adjustable between said one movable member and the circuit member to position one of the scales on said other movable member with relation to the adjusted scales of said one movable member and thereby to determine the potential necessary to produce the radiation required for the X-ray of the part involved.

IRVING RNGLER.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 659,727 Brown Oct. 16, 1900 668,896 Wager-Smith Feb. 26, 1901 1,210,488 Kelly Jan. 2, 1917 1,236,051 Campbell Aug. 7, 1917 1,478,1956 Harrold Dec. 25, 1923 1,609,972 Sherrer Dec. 7, 1926 2,136,116 Mowry Nov. 8, 1938 2,319,322 Hefel May 18, 1943 2,365,554 Jeans Dec. 19, 1944 FOREIGN PATENTS Number Country Date 167,099 Great Britain Aug. 4, 1921 OTHER REFERENCES Pages 241-246 both inclusive, of Industrial Managemen of November 1917, published by The Engineering Magazine Co. of No. 6 E. 39th St., New York, N. Y.

Pages 42 and 43 of the Jan. 11918 issue of Industrial Management.

Page 389 of the December 1917 issue of Industrial Management.

Note: There is an article by A. L. Jenkins on the aforesaid pages, the title of which is Design of Special Slide Rules.

Certificate of Correction Patent No. 2,455,522. December 7, 1948.

IRVING RIN GLER It is hereby certified that errors appear in the printed specification of the above numbered patent requiring correction as follows:

Column 5, line 34, for SK Nr read SK N 0:; line 37, for No-SC-16 read No-SO 16; line 41, for HO-34 read H0 34;

and that the said Letters Patent should be read With these corrections therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 24th day of May, A. D. 1949.

[IML] THOMAS F. MURPHY,

Assistant Commissioner of Patents.

Certificate of Correction Patent No. 2,455,522. December 7, 1948.

IRVING RIN GLER It is hereby certified that errors appear in the printed specification of the above numbered patent requiring correction as follows:

Column 5, line 34, for SK Nr read SK N 0:; line 37, for No-SC-16 read No-SO 16; line 41, for HO-34 read H0 34;

and that the said Letters Patent should be read With these corrections therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 24th day of May, A. D. 1949.

[IML] THOMAS F. MURPHY,

Assistant Commissioner of Patents.

Certificate of Correction Patent No. 2,455,522. December 7, 1948.

IRVING RINGLER It is hereby certified that errors appear in the printed specication of the above numbered patent requiring correction as follows:

Column 5, line 34, for SK N z read SK N 0:; line 37, for No-SC-l read No-SO -16; line 41, for HO-34 read H0 34; and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 24th day of May, A. D. 1949.

THOMAS F. MURPHY,

Assistant Gommzssz'oner of Patents. 

